Somewhere out there, alien civilizations might be communicating with each other. They might even be trying to contact us. Fifty years ago, this reasoning compelled astronomer Frank Drake to point a radio telescope at the stars and listen for chatter. He didn’t hear E.T. calling us, calling home, or calling anywhere else during his four-month-long experiment at the National Radio Astronomy Observatory in Green Bank, W.Va., but the effort officially kicked off what is known as SETI, the search for extraterrestrial intelligence.